It is difficult comment without knowing the equipment being installed and how much work is needed to install the new duct work. It this system working with a boiler for heating? Can you provide the equipment list?

The 13 SEER AC suggests lower end equipment. It may be fine depending where you are located in New York. Not sure what "New York environmentally friendly" is supposed to mean. I don't think New York State is dictating unfriendly equipment is not allowed.

The system will be working with a tankless water heater. I just requested the equipment list from my contractor. The house is a split level home and there are currently no ducts or returns in the basement. What information do you need to estimate the amount of work to install the ducts?

New York City or New York State? If the latter, what town?

West Hempstead

The length and widths of the new ducts and the number of supply and return registers would be useful information. But even with that information I am not sure you will get many comments. Perhaps you can ask for a quote where the duct work is broken out as a separate line item.

I am familiar with split level homes on Long Island. Did the house originally have no duct work? Was it originally base board heating with window AC?

Is the tankless hot water heater supplying both domestic hot water and the hot water for the heating coil? I sense you are trying to find out $18,500 is reasonable, but I suggest you provide information on what heating and cooling equipment has been proposed and let's see if it the best choice for your house and location.

"Install New York environmentally friendly 13 Seer 4-ton split air conditioning
system"

I don't know what a "New York environmentally friendly" 13 Seer 4-ton split air conditioning system is, but it smacks of BS marketing speak (especially if it's a bottom of the line 13 SEER system).

Can not help you on the amount of the dollars because too many variables, but I can tell you 13 SEER is not acceptable even 10 years ago.

but I can tell you 13 SEER is not acceptable even 10 years ago.

Well AC SEER rating choices are complicated subjects due to location / climate concerns. The higher the SEER of the AC the higher the cost. Certainly cost of operation, what is paid to run it should be considered as well.

With a 3 month at best AC season for some areas you can reach a point of "no return" meaning you spend money for efficiency that never pays for itself. From there you have to decide what "comfort" means to you. No one is the same in that regard.

In terms of cost? what is fair, what is not fair in terms of that price? Each job is different... this one new ductwork, zoning... environmentally friendly?

I doubt that. I bet it contains R410a - that is on the chopping block for GWP concerns. (Phase down, phase out, Ban) -- no matter what verbage you use... it's the same thing poor old R22 went thru.

Outside of price what is fair? It works. This happens via workmanship, installation, technicians, contractors knowing what they are doing.

I service the Katy, Texas area.

I would call 5 Star Mechanical on Long Island. We just had ours done. They did a excellent job with quality materials for a good price. There are differences in price is because of the quality of materials they use and how it’s installed. I don’t think 13 seer is up to code now . I would go with 16 seer .